FAQ:Why does my audio sound bad/choppy/crackle?
Note that audio problems can also occur if you have a bottleneck which decreases the data transfer rate of your hard drive. Try moving your problem audio clip to another hard drive as a test. *See the Audio page for more troubleshooting tips. *The following originally appeared in the Adobe Forums: Audio Poor Quality Audio Tracks Play with Static and Low Quality in Premiere Issue Audio tracks play with low quality (e.g., static, noise) when played simultaneously with the video track of a captured movie clip in Adobe Premiere. The audio tracks play independently as expected. Solutions Do one or more of the following: A. Capture the movie at a lower data rate: 1. In Premiere, choose "Movie Capture" from the "Capture" submenu of the File menu. 2. Choose "Recording Options..." from the Movie Capture menu. 3. In the "Recording Options" dialog box, click "Video Format...." 4. In the "MJPEG Settings" section of the "Video Format" dialog box, specify a lower "Data Rate" value, then click "OK" to close the remaining dialog boxes. 5. Recapture the movie. B. Capture the audio at a lower sample rate: 1. In Premiere, choose "Movie Capture" from the "Capture" submenu of the File menu. 2. Choose "Audio Recording Options..." from the Movie Capture menu. 3. In the "Audio Options" dialog box, select "16 Bit - Mono" from the "Rate:" drop-down menu, then click "OK" to close the remaining dialog boxes. 4. Recapture the movie. NOTE: If the audio still plays with lower quality when played with video, select a lower format (e.g., 22 kHz) from the "Format:" drop-down menu in the "Audio Options" dialog box and recapture the movie. Additional Information Some sound and video cards use Direct Memory Access (DMA), a method of transferring data from a device to memory without using the microprocessor, thus improving performance. When both sound and video cards use DMA and share resources, the video takes precedence so sufficient resources for the audio are not available, decreasing the quality of the audio playback. Decreasing the amount of data being processed by capturing the audio or video at a lower data rate prevents the sound and video cards from having to share resources. (From Adobe Support) If you changed the sample rate, or the bit rate, of the audio ... in my experience it will sound poor if the conversion is done by Premiere. (RGBaker - Dec 15, 2003) Your audio is exceeding the peak value allowed in DVD audio and it's clipping. If you switch to audio editing mode (it's one of the options in the window menu, can't remember it offhand), and adjust the volume such that the red peak indicator lights are never lit (while you're playing through your timeline, they will stay on once the peak threshold is hit, and they aren't reset until you stop and hit play again), it will sound fine when you export to DVD. (mr_donk - Dec 15, 2003) Reduce the overall project volume to make sure that you do not exceed 0db. You can do this from the Audio Mixer in the Audio Workspace. You can also apply the Dynamics effect to the master audio track in the Audio Mixer and use the limiter to ensure the audio will not exceed 0db. (RogerW - Feb 5, 2004) Well I found the problem with my sound. I have the Canopus DV REX TR and they have a Audio patch that helps with the newer motherboards with intel chipsets with intergrated audio. I ran the patch and my audio sounds great. (Bill Tortorello - Feb 12, 2004) I found that if you export your audio into a wave file, unlink your current video and audio, delete your current audio, and inport your new wave file, everything works good. (Clayton - Feb 22, 2004) I have been dreading this problem but it has not shown up. I regularly split out my audio to two mono channels (different mics on the two channels) then bring the video and audio into the timeline seperately. (Mike Cook - Feb 23, 2004) I was able to work around this problem by outputting the audio as a WAV file and then using that WAV file in the DVD authoring software -- instead of using the WAV file created by Premiere during the Video/Audio output to AVI or MPEG-2 (Thumper Strauss - Dec 25, 2003) I had the same problem, if you have more than one audio track and you render out to dv avi-file with audio imbedded, there is random crackling in the movie. When i export only the audio tracks to wav, then delete the content of the audio tracks and reimport the rendered wav-file, and then export the movie as dv avi-file, there is no crackling. I first thougt, it was my soundcard and I spent money on a new one. But it did not help. I think this is a serious bug in PPRO and that should be fixed. The bug occurs often at that frames in the timeline, where i change the volumes for different channels in the audio-mixer. Hope, the developement stuff of Adobe is listening here. (Bernhard Kaulfuss - Dec 27, 2003) One remedy for the audio cracks and clicks/pops etc caused by this Adobe problem is this: I exported my entire audio track (from the timeline)to Cool Edit Pro, or you could use Adobe Audition - same thing; select the filter that takes out the clicks - save the file - bring it back into Ppro and sit it right on the timeline where your original audio track was.Sync wise, it will line up exactly with the picture, especially if you have "snap to" enabled. Its not the way things should be done , but it does bring your audio back to normality. (Steve Oxley - Jan 23, 2004) I solved the crackling by lowering the master volume 6 db in the audio mixer. My projects contain a music track in addition ro the audio track from the camcorder. Apparently, volume levels are additive in the traks; hence, the crackling. (Robin Wulffson - Feb 3, 2004) Well I found the problem with my sound. I have the Canopus DV REX TR and they have a Audio patch that helps with the newer motherboards with intel chipsets with intergrated audio. I ran the patch and my audio sounds great. (Bill Tortorello - Feb 12, 2004) Another method you might try is to insert an audio effect onto the master audio track. From memory PPRO has a 'Dynamics' plugin. Just use the limiter function of this effect and set the threshold below 0dB (perhaps -0.5 or -1dB to be safe). (Simon Cohen - Feb 23, 2004) I found that if you export your audio into a wave file, unlink your current video and audio, delete your current audio, and inport your new wave file, everything works good. (Clayton - Feb 23, 2004) -12db is often cited as a good peak level. (RogerW - Feb 24, 2004) In cases where excessive levels are the problem (not always the case from reading the above), reduce the level of mixed tracks to avoid the summed levels going over the top (as advised above), but try putting the limiter on the master track to catch anything unexpected. In the Dynamics effect, have only the limiter ticked, set the level to (say) -0.1dB, and the release at (say) 250ms. I've been running some tests with a short video originating from a TV program recorded onto a DV camera, captured into PP1.0, which results in audio peaking exactly to 0dB. If I export a section to a DV AVI file with the mixer faders set to zero dB, then open up the audio using Audition, it can be seen that there is no change in the level of audio either up or down resulting from the export - which is fine and as it should be. If, however, the file is exported with the audio track fader set to +1dB (which gives red clip indicators in the PP mixer but sounds ok), and then opened in Audition, sharp clicks are heard at the points of overload. Zooming right in to the detail of the waveform it can be seen that instead of the audio clipping normally (resulting in a flat line at the top or bottom of the waveform), the waveform suddenly reverses phase at the point where overload occurs, and this is what causes the unpleasant click. I'm no expert in the theory of digital audio processing but I rather suspect that there is an error in the underlying maths in the program's DSP which does not handle an overload situation very elegantly. (That's a long-winded way of saying "it looks like a bug"). I've also experimented using a VST effect on the master track called "TapeIt" - this allows one to divert the audio at the point where the effect is inserted straight to a wave file on disk, in effect recording the audio playing back from the timeline. This shows that during playback from the timeline, if an overload is provoked, the program handles it much more as one would expect, and mild clipping is not clearly audible, unlike in the export situation. The answer remains that, to avoid these problems altogether, don't allow your exported audio to clip. Reduce levels, and perhaps use the limiter as a safety net. I've just tried that in the "+1dB" scenario and the result is the removal (or rather avoidance) of the clicks. (Ozpeter - Jun 6, 2004) It's actually slightly worse than it seems, and it appears to be a problem with the relationship between PP1.0 and its AVI codec, or possibly in fact just a codec fault. If you take a 'normal' file, and set a suitable level of normalise boost within PP to get it to clip slightly, you then have two options open to you for exporting. Firstly you can export it as a WAV file, and also you can export as an AVI. If you export the WAV file and open it up in AA, then it sounds just like the PP replay - okay, it's a bit clipped, but nothing too untoward is happening. Then with identical settings, you export the AVI. And oh boy, what a racket! With my file, I added 6.1dB of gain for the export, (same as for the WAV) and the cracks start to appear well before you hit 0dB. I don't think this is a straightforward 'hit the top and bounce off' situation at all. And it's definitely in the PP coding process, it's got nothing to do with AA at all. How do I know this? Beacuse I opened up the resultant AVI file in Pinnacle Studio 9 and got the same horrible noise out of it... So yes, it's a PP bug, and one that really should be attended to with some urgency if it isn't fixed in 1.5 (which I don't know) (SteveG - Jun 7, 2004) Sorry, but if you set anything to +1dB, then you are actually going over 0dBFS which as long as you are in 32bit Floating Point is not a problem. This is why it will still sound okay in Preview within Premiere, as you are still in FP mode with a theoretical 1000dB headroom and it is virtually impossible to clip. However, the minute you drop this to fixed point you will get distortion. This is not a bug, this is standard Digital Audio theory. NEVER go right up to 0dBFS, as this leaves you with nowhere to go and absolutely zero headroom. Try to keep your audio peaks at no higher tham -3dBFS. Strange as it may seem, when you EQ a file at 0dB - even if you cut a frequency - because of the masking phenomenon, the actual peak level of the resulting file can go UP. Also, if you are adding 6.1dB of gain, you have increased the volume by over 100%. May I suggest that you set your input gain a little higher? There is not a bug here, this is a simple misunderstanding of digital audio theory I'm afraid. (Neil Wilkes - 03:48am Jun 7, 2004) silly and factually incorrect statements like that. The 32-bit FP system has a theoretical dynamic range in excess of 1500dB, not 1000dB, and anyway, this is all completely irrelevant. So let me spell it out for you: 16-bit (integer) WAV file exported from PP - slight clipping, but it sounds reasonably okay. 16-bit (integer) file incorporated in AVI has the same overall exported level and makes the most awful racket well below 0dB, never mind over it. I know that you shouldn't export clipping files. I also know that the way they clip should be identical, and not have added clicks and farting noises. I am not suggesting that this is good practice at all - but it certainly shouldn't cause this to happen. Also, if you are adding 6.1dB of gain, you have increased the volume by over 100%. May I suggest that you set your input gain a little higher? You may suggest what you like - but since a) this was only a test file, and b) I wanted to make it clip, I think you'll find that it was recorded sufficiently close to 0dB already. Never heard of headroom? No, probably not... even though you mentioned it! (SteveG - Jun 7, 2004) I believe that all of what is being reported here is a bug/behavior that was fixed in 1.5 (I didn't see anyone who had reported it using 1.5, but speak up if you did). Here is what is going on: Everything in PPro internally works in 32 but floats, which means that values over 1.0 (0 dB) are completely legal and maintained. However, if you export or play to an integer format, like most files and most soundcards, the floats have to be turned into ints. You have two choices: let the integer values wrap negative, or replace every value above 1.0 with the maximum positive integer - i.e. clip. In 1.0 there were several paths for output which used wrapping, not the preferred method, clipping. These are some of the paths that you have identified. All of these paths have been changed to clipping for the 1.5 release. Note, please, that it is still possible for a 3rd party plugin to wrap instead of clip. They get floats from Premiere, and what they do with them afterwards is up to them. If anyone is still seeing this behavior in 1.5, please contact me directly so that I can understand the situation. (Mike Berry, Audio Engineer, emiere Pro, mberry@adobe.com Jun 7, 2004) A postscript to the above discussion - at http://www.elementalaudio.com you can download a free VST 'effect' called "Inspector" which will monitor your audio as you play your sequence, and, among other things, tell you by how much you have exceeded the 0dB maximum permitted level. You can then reduce the monitored fader by that amount and be confident there should be no clipping. It comes remarkably well documented (for freeware) and the help file is worth a quick check through. And another tip - if you export just the audio of your project with the "Inspector" vst window visible, it will provide the analysis of levels and clipping at high speed - on my PC, in about 4 mins for a 40 minute .avi - and the results it gives correlate with analysis in Audition, so it appears you can depend on it. In my test file, it showed that the level needed to be reduced by 0.4dB to avoid clipping - which was the amount by which I'd pushed the fader up before running the test. Using this method it would appear you don't have to sit glued to the meters all the way through your project to avoid clipping. (Ozpeter - Jun 10, 2004) Category:FAQ Category:Audio